Light-Regulated Sensor Histidine Kinases - Structure, Dynamics & Optogenetics

信号受体包括对化学或物理刺激作出反应的传感器模块和具有生物活性的效应器模块。传感器和效应器之间的相互作用是生物活性信号依赖调节的基础，全面的生化、生物物理和结构表征必须涉及完整的传感器效应器实体。我们的重点是光感受器作为光遗传学中的光调节致动器。通过采用工程光氧电压光感受器YF1作为范例，我们利用了我们最近确定的全长蛋白的黑暗适应结构。我们试图阐明支持信号转导的构象和动态转变，以及它们如何导致效应活性的调节。光适应态和反应中间体的结构信息将通过x射线晶体学获得。同时，我们将通过功能分析、电子顺磁共振、红外光谱和氢-氘交换的组合来探测信号转导的动力学。在分子动力学模拟的指导下，结构和动态数据将被调和，以揭示光敏器和效应器如何通信。YF1的结构和机制原理在多种信号蛋白中反复出现。提高对信号转导基本方面的理解将有利于光感受器的合理工程及其光遗传部署。

Signal receptors comprise sensor modules which are responsive to chemical or physical stimuli and effector modules which possess biological activity. Interactions between sensor and effector are at the very basis of the signal-dependent modulation of biological activity, and a comprehensive biochemical, biophysical and structural characterization must involve intact sensor-effector entities. Our focus is on sensory photoreceptors which serve as lightregulated actuators in optogenetics. By employing the engineered light-oxygen-voltage photoreceptor YF1 as a paradigm, we capitalize on the dark-adapted structure of the full-length protein we recently determined. We seek to elucidate the conformational and dynamic transitions underpinning signal transduction and how they lead to regulation of effector activity. Structural information on the light-adapted state and reaction intermediates will be obtained by X-ray crystallography. In parallel, we will probe the dynamics of signal transduction by a combination of functional assays, electron paramagnetic resonance, infrared spectroscopy and hydrogen-deuterium exchange. Guided by molecular dynamics simulations, structural and dynamic data will be reconciled to reveal how photosensor and effector communicate. Structural and mechanistic principles evidenced in YF1 recur in diverse signaling proteins. An improved understanding of fundamental aspects of signal transduction will thus benefit the rational engineering of photoreceptors and their optogenetic deployment.